The Royal Swedish Academy of Sciences awarded the 2025 Nobel Prize in Chemistry to Susumu Kitagawa, Richard Robson, and Omar M. Yaghi for their pioneering research on metal-organic frameworks (MOFs). So what exactly are MOFs? And why do they deserve a Nobel Prize?
MOFs are crystalline powders filled with tiny, molecule-sized pores. They have a unique structure: a porous framework where metals are connected by organic linkers. If you take one gram of MOF and spread out its internal surface area, it would cover more space than a football field. Because of their highly tunable structure and extraordinary porosity, they have attracted widespread research interest in materials science and chemistry.
Basic Components of MOFs
The structure of MOFs can be thought of as a molecular-scale “scaffold.” Its construction requires two core components:
- Metal Nodes: These are metal ions or small clusters of metal atoms that act as support points or junctions in the structure. Common metals include zinc, copper, iron, chromium, and zirconium.
- Organic Linkers: These are rigid organic molecules, often containing multiple functional groups—such as carboxyl or nitrogen-based groups—that can coordinate with metal nodes. They act as “pillars” or “beams” connecting the metal nodes.
By selecting different metal nodes and organic linkers, and by controlling synthesis conditions, researchers can design and produce MOF materials with varying pore sizes, channel structures, and chemical properties.
Key Properties of MOFs
MOFs have attracted significant attention mainly due to the following key characteristics:
- Extremely High Specific Surface Area: MOFs are among the materials with the highest known specific surface areas. The internal surface area of one teaspoon of certain MOFs can exceed the area of a football field. This provides ample space for gas adsorption, substance loading, and chemical reactions.
- Highly Ordered Crystal Structure: MOFs are crystalline materials, meaning their atoms and molecules are arranged in a regular, repeating pattern in three-dimensional space. This allows scientists to precisely determine their structure using techniques like X-ray diffraction.
- Tunable and Functionalizable Pores: The pore size and chemical environment of MOFs can be precisely designed and adjusted by changing the types of metal nodes and organic linkers. Additionally, the inner walls of the pores can be chemically modified after synthesis to introduce specific functional groups, enabling customization of material properties.
Applications of MOFs
MOFs are well-suited for detecting and capturing/adsorbing substances at very low concentrations, purifying water or air, and storing large amounts of energy for better batteries and energy storage devices. Scientists have designed over 88,000 precisely tailored MOFs, with applications ranging from agriculture to pharmaceuticals.
- Gas Storage and Separation: MOFs can adsorb and store energy gases such as hydrogen and methane. They can also efficiently separate mixed gases—for example, capturing carbon dioxide from power plant emissions or separating oxygen and nitrogen from air.
- Catalysis: The large surface area and designable active sites of MOFs make them excellent catalysts. Metal nodes or modified organic linkers can serve as catalytic centers to accelerate chemical reactions.
- Chemical Sensing: When specific molecules enter the pores of MOFs, they cause changes in physical properties—such as fluorescence or electrical conductivity. These changes can be used to detect trace amounts of gases, vapors, or ions.
- Drug Delivery: The porous structure of MOFs allows them to load therapeutic drug molecules and achieve controlled release under specific conditions in the body—such as changes in pH—improving drug efficacy and reducing side effects.
Summary
Metal-organic frameworks are a class of porous crystalline materials formed by coordinating metal nodes with organic linkers. Their core value lies in their designable structure, extremely high specific surface area, and tunable pore chemistry. These properties make MOFs a highly promising platform material for addressing challenges in areas such as gas storage, separation, catalysis, and biomedicine. For more industrial news and tech support, please check Stanford Advanced Materials (SAM).
